Damper worry

[Fingolfin]

Been up draining and filling one of my nice Armstrong rear dampers. Placed it in a vice, undid the fill and drain plugs (watching the valve in the drain plug), worked the arm to get the old (horrid smelling) oil out, made a paper funnel and filled it up again. Two things then happened I wasn't expecting:

1) The new oil never came out, even after five minutes of constant pumping on the arm and topping up all the way. It was just old black gunk that dripped every once in a while. So, replaced the plugs and found that the arm became almost immobile, which is what I wanted, but...
2) Some oil leaked out at the arm joint, and continued to do so under pumping. About three drops for a full 90º movement.

So what's gone wrong? Do I need a reconned damper? Is it possible that I've overfilled it and that's causing the leak?

[bmcecosse]

No - the old oil was probably leaking too - but was so thin/horrible it didn't put any great pressure in the system and so the leak was minimal. You really need to flush the old oil out with new over a period of time - the leak probably won't 'heal up' - but if it's not too bad - just live with it and top up from time to time.

[chickenjohn]

Agreed, the lever arm dampers soldier on for years even when they are leaking slightly. As long as that corner of the car is still damped, don't worry, just top up and wipe dry before each MOT (if you have an MOT where you are!).

[Fingolfin]

Haha, we do have inspection for license plate renewal, which is once a year. But it's not near as extensive as your MOT appears to be...the main things are if you have working lights and a good structure. They don't do welding if you have rust holes, you have to have that done on your own expense. I'm certain they don't look for leaks on dampers!

Nonetheless -- you've put my mind at ease. For once it's not a disastrous thing I've discovered!

[chickenjohn]

Haha, we do have inspection for license plate renewal, which is once a year. But it's not near as extensive as your MOT appears to be...the main things are if you have working lights and a good structure. They don't do welding if you have rust holes, you have to have that done on your own expense. I'm certain they don't look for leaks on dampers!

Nonetheless -- you've put my mind at ease. For once it's not a disastrous thing I've discovered!

Good! The rear dampers on my Traveller have been weeping for years and I just top up and wipe from time to time and it has never failed the strict British MOT on leaking dampers. As long as the car isnt bouncing all over the place! A saloon should ride fairly smoothly, yet firmly as it has less weight than the Traveller and a 5 leaf springs at the back.

[Fingolfin]

I'd forgotten entirely about this thread! But I suppose I ought to revive it, because now I've got issues with the front dampers. The problem is, they are leaking badly from around the arm -- the engine bay floor has a thick sheen of oil on either side, with trails going up to the dampers, and a wet streak running from the arm aperture down.

I read Declan's excellent thread on renovating dampers, and that looks like a possibility (I don't have a press myself but maybe I could have a local machine shop do it), but aside from that do I have any options? I should mention that I do have two condition-unknown (but they look good on the outside -- repainted by the fella I got them from) spare front dampers -- should I fill those up and fit them to the car?

The rear dampers still seem to be functioning and not leaking very much, though.

[bmcecosse]

Yes - I would fit the spares -filled with nice new SAE 40 oil.

[Fingolfin]

Aye, I'll do it one weekend when I'm free from uni. It's sort of bittersweet though -- the front dampers were the only bolt-on items I didn't remove from Mog when I did its stripdown.

[JOWETTJAVELIN]

Consider the leaking dampers to be ongoing rust-prevention (as long as the leak isn't excessive, of course).

[Fingolfin]

It seems to me that the leak is tremendously excessive -- I think the dampers leak about a milliliter a day, and the engine bay floor (and the suspension) is simply soaked and dripping. But you make a good point, Jowett.

[Fingolfin]

I tested one of the spare front dampers, and curiously I could get absolutely no pressure in it -- the arm just goes up and down with light finger pressure -- despite having filled it up with SAE 30. Not sure what to do about that, but I suppose it means for now the original front dampers are staying on...at least they dampen!

[bmcecosse]

Is there a valve assembly in the base? It may take a little pumping to get the new oil right round the damper...keep pumping!

[Trickydicky]

Dont know if this would work but it could be worth a try, fill the damper as per usual from the top and replace the plug, then with the damper on its side with the valve assembly pointing up in the air, fill the damper from the valve assembly, replace the valve and test.

It could be that the valve (ball bearing) in one of the pistons is sticking and reverse filling the damper then pumping may be enough to fix it.

You have nothing to lose!!

[Declan_Burns]

Fin,
There is a proper seal now available for the front dampers which took me ages to source. It's a 28x38x7mm lip seal and it only costs 1.80€. I fitted one last Saturday.
Regards
Declan

[bmcecosse]

Aye -but it can only hope to hold if the shaft bushings are good. Worth a try - but not everyone has the big press to get the arm out!

[Declan_Burns]

True with the bushing but I have not come across many where they were damaged. A large puller might even work. If you get the shaft moving it's easy enough. It doesn't have to be pressed that far~1/2" or less and then it's free. It is obviously a lot easier with access to a press.
If anybody wants to tackle it and can't get the seals PM me.
Regards
Declan

[Fingolfin]

Declan, thanks for that. Is this roughly what you're talking about? http://www.ebay.com/itm/U32i-Metric-Sin ... 0486438316 That's polyurethane -- not sure if one must use rubber. I figure poly would last far longer before leaking.
I could probably have the local machine shop press the shafts out. I recall you had to drill out the cover behind the shaft -- where did you source the replacements for the covers?

[Declan_Burns]

Figolfin,
That could be OK but it depends on the fit on the outside diameter. I tried a solid PU seal (see photo below) and it turned against the housing with the shaft even though I used Hylomar sealant. Now I just use ordinary spring loaded rubber lip seals. Check the fit as the seat measured 37.6mm. The ones I used were quite a snug fit as they have an internal metal reinforcing and so don't move. It is always easier to take a whiff of a seal than modifying a housing. Just make sure that before they press the shaft out that they empty the damper and move the arm to the end of travel and mark the shaft and the housing alignment clearly with a centre punch. Take plenty of photos if you can. For the covers you can use 25mm domed core plugs but they should be no thicker than 3mm to clear the bulkhead. You can use PVC or aluminium and turn it down to OD 25.2mm. Chamfer the front edge and carefully cut to 3mm with a parting tool. It took me a bit of practice to get that right I must admit and is quite time consuming! It's a lot easier if you can source a ready made plug.
Regards
Declan[frame][/frame]

[Fingolfin]

That's very useful, Declan -- thank you. Where did you source the spring loaded rubber lip seals?

[Declan_Burns]

Fingolfin.
Any bearing dealer should be able to supply them. Here's the link to where I buy them but it is in German.
http://www.ir-dichtungstechnik.de/shop1 ... cts_id=376
If you can't find them locally let me know.
Regards
Declan